Device for regulating the tension of paper webs



Jan. 10

F. FUCHS v DEVICE FOR REGULATING THE TENSION OF PAPER WEBS Filed May 14, 1927 2 Sheets-Shet 1 Jan. 10, 1928. 1,656,111

F. FUCHS DEVICE FOR REGULATING THE TENSION OF PAPER WEBS Filed May 14, 1927 2 Sheets-Sheet 2 wll'llllllll Patented Jan, 10, 1928.

UNITED STATES FRIEDRICH FUCHS, F ZOFINGEN, SWITZERLAND.

DEVICE FOR REGULATINGi THE TENSION OF PAZPER WEBS.

Application filed May 14, 1927, Serial No.

The present invention relates to improvements in devices for regulating the tension and particularly for automatically maintaining constant the tension in a web of a paper to he printed.

With webs of paper to be printed variations in the tension of the Web occur almost continuously, which may be caused from various reasons, for instance by the irregular in lbralcing action of the brake band on the hrake pulley on the axle of the roll of paper,

or loy the reduction in the diameter of the roll of paper during the unwinding, or by a difierence in the tightness of the winding it of the paper roll itself. Particularly the last two conditions render it impossible to obtain a totally uniform tension oi the web solely by the actuationof a brake device,

when this actuation is left to the discretion cc of the attendant.

' The "known unwinding device, in which the roll of paper is so driven by a wide belt that the speed of the web corresponds to the circumferential speed of the printin cylini ders, does not permitto maintain t e tension oi the web sutliciently uniform as is for instance required "for avoidin the diiierences in the register with multi-color printing, as with the smallest variation in its tentil sion the web stretches or shrinks which oloviously causes differences in the register. Further experience has shown that in multicolor printing the principal variations in the register are due to the continuously occurring variations in the tension of the web so that overcoming these variations in the tension permits at the same time multicolor printing with rotary presses.

it is therefore the object of the present till to invention to provide an arrangement lay means oi which the tension of the web is automatically maintained constant.

The arrangement according to the present invention comprises a movably mounted dett vice over which the web slides and which is provided with means adapted to hold the device in a determined position for determined tensions of the weh, further controlling means are provided which respond to a variation of the position oil the device caused by a variation of the tension and which actuate hralring means acting on the paper roll in such a manner that the variation of the ten sion is counteracted.

The device is preferably construct as a 191,435, and in Switzerland April 7, 192?.

rotataloly mounted drum to which an arm is fixed carrying a sliding Weight by the ad justment of which the drum is held in a determined osition which corresponds to a determine tension of the web.

A constructional example of the subject matter of the present invention is illustrated on the accompanying drawings, in which:

Fig. 1 shows in elevation part of a multicolor rotary printing press, having the arrangement for automatically maintaining constant the tension of the web fitted thereto, and the diagram of the electric connections,

Fig. 2 is an axial section of the regulating drum,

Fig. 8 shows in an end view the drum and the arm fixed to the latter,

Fig. 4: shows in a plan view the pointed end of the arm,

Figs. 5 and 6 show in trout and side "T vation respectively with parts shown in section the means for actuating the hralre oi the paper roll,

Figs. 7 and 8 show in front elevation and in a vertical section respectively a detail oi the controlling device, and

Fig. 9 is an end view oi the support of the paper roll showing the loralre for the latter.

The welo l is unwound from theroll of paper 2 and runs over the guide rollers 3, 4t and 5 to the first printing mechanism it and from the latter over thedrying drum 6 and guide rollers 7, 8 and 9 and slides over the regulating drum l0 and from there runs over the guide rollers ll and 12 to the second printing mechanism B and from there for instance to further printing mechanisms not illustrated. The drive of the printing mechanisms is efl ected by an electric motor 13 through the interposition of a numher oil gear wheels 14-.

The regulating drum is rotatably mounted in hall bearings 15 and 16 provided in the parts 1'? of the side shields of the printing press. The axle 18 of the drum extends beyond the part 17 of the frame and on this axle an arm 19 is fixed. Along the arm 19 a sliding weight 20 is displaceahle and is so adjusted that the arm remains in a determined position, for instance pointing towards the zero-point ot the scale Ql provided on the frame part ll (l i ll, where by the turning moment oil the sliding weight 20 and ot the arm it halancea the triction till till

till

'lllll lllti lift action of the web on the surface of the drum tending to turn the drum with a determined over a brake pulley 24 rigidly fixed to the axle 25 of the roll 2. The axle 25 rests in supports 26 to which one end ofthe' brake band 23 is fixed at 27. To the other end of the brake band a rack 28 is fixed which is movable in the vertical direction in a guidance 29 in order to tighten or slacken the brakeband.

With the rack 28 cooperates a toothed seg ment 30 turnable about a pin 31 fixed to the support 26 and arranged at the end of a twoarmed lever to the other arm 32 of which a screw threaded spindle 33 is linked.

The pointed end 34 of the arm 19 (Figs. 3 and 4) is connected to the other part of the armby means of an insulating piece 35 and is provided with a binding screw 36 to which a wire 37 is connected, above and below the point 34 of the arm 19 contacts are arranged shown in detail in Figs. 7 and 8. Each contact comprises a contact pin in the form of a set screw 38 or 38'- respectively adjustable in'a metallic angular piece 39 mounted on a board 40. Each board is further provided" with a binding screw 41 and 41 respectively to which the conduits 42 and 43 respectively are connected. The conduits 37, 42 and 43 lead to. relays 44 and 45 respectivel of theswitches 44 and 45' respectively w ich are inserted in the supply mams leading to a three-phase electric motor 46. As may be seen from the diagram of connections illustrated in F1 1 two phases of the current are exchange in the switch 44' in comparison to the switch 45' so'that whenclosing the latter the motor 46 rotates in-one direction and when closing the switch 45 the motor rotates in the opposite direction.

On the shaft of the motor 46 a .worm 47 (Figs. 5 and 6) is fixed which cooperates with a worm wheel48 loosely mounted on a vertical shaft 49, the lower end of which hasa bore 50 provided with interior thread with which the spindle 33 cooperates. The shaft is mounted in a support 51 and is provided at its upper end with a knob 52 rigi ly fixed thereto. Further on the shaft 49 and secured a inst rotation by a feather 53 one half 54 o a claw clutch is displaceable, the teeth of the, clutch cooperating with correspondingly sha teeth formed in the nave of the worm w eel 48. When the clutch is engaged the shaft 49 is turned in one or the other direction by the motor 46 and the brake on the paper roll is tightened or slackened, when the clutch is disengaged the brake may be adjusted manually by turning the knob 52.

As soon as the tension in the web decreases the friction generated on the drum 10 decreases also, the sliding weight predominates, the arm 19 is lowered and its pointed end 34 bears on the lower contact pin 38, whereby a circuit through relays 45 and switch 45 is closed and the electric motor 46 is causedto rotate in such a direction that the brake on the paper roll is tightened; on the other hand when the tension of the web increases the friction action of the paper on the drum 10 predominates, the arm 19 is lifted to bear on the upper contact 38 and a circuit over relays 44 and switch 44 to the motor is closed, whereby the latter is rotated in a direction which causes a slackening of the brake on the paper roll. The actuation of the brake in one sense or the other lasts only for such a time until the original tension in the. web has been re-established, whereupon the arm 19 returns into its mid-position and the circuit to the motor is again interrupted.

The above described arrangement is very sensitive and responds to the smallest variations in the tension of the web so that the tension may be practically maintained constant. As in this case no stretching or shrinkage of the web occurs the arrangement of the present invention causes a good register and the possibility of producin multicolor prints on rotary printing 111215111168.

I claim:

1. An arrangement for automaticall maintaining constant the tension in the we of paper unwound from a roll of paper, comprsing in combination, brakin means adapted to act on the roll from w ich the web is'unwound, a movably mounted device over which the web slides, means on said device adapted to counteract the friction action caused by the web sliding on said device, a controlling device influenced by said means on said device and including electric circuits, and an electric motor operatin said braking means and controlled by sai controlling device.

2. An arrangement for automatically maintaining constant the tension in the web of paper unwound froma roll of paper, com prising in combination, braking means adapted to act on said roll of aper, a rotatabl mounted drum over w ich the web sli es, adjustable means on said device .to counteract the friction action caused by the web sliding on said drum and adapted to hold said drum in a determined position for a determined tension of the web, a controlling device with which said adjustable means cooperate as soon as a variation in the tension of the web occurs, and an electric motor operating said braking means and controlled by said controlling device.

3. An arrangement for automatically maintaining constant the tension in the web of paper unwound from a roll of paper, comprising in combination, braking means adapted to act on said roll of paper, a rotatahly mounted 'drum over which the web slides, an arm on said drum and a sliding weight on said arm for counteracting the friction caused by the web sliding on the drum and adapted to hold said drum in a determined position for a determined tension of the web, contacts with which said arm cooperates as soon as an alteration of the tension of the welo occurs, an electric motor operating said braking means, and electric circuits interposed between said contacts and said electric motor and comprising switches and relays operated by said contacts, one of said circuits having the phases exchanged as compared with the other circuit for reversing the motor.

a. An I arrangement for automatically maintaining constant the tension in the web of paper unwound from a roll of paper, comprising in combination, braking means adapted to act on said roll of paper, a rotatably mounted drum over which the web slides, an arm on said drum and a sliding weight on said arm for counteracting the friction caused by the web sliding on the drum and adapted to hold said drum in a determined position for a determined tension of the web, contacts with which said arm cooperates as soon as an alteration oi the tension oi the welov occurs, an electric motor, transmission means interposed hetween said electric motor and said braking means, a clutch interposed in said transmission means for cutting out the motor when said transmission have to be operated by hand, and electric circuits interposed between said contacts and said electric motor and comprising switches and relays operated by said contacts, one of said circuits having the phases exchanged as compared with the othercircuit for reversin the motor.

in testimony whereof, have signed my name to this specification.

. FRIEDRICH FUCHS. 

